Apparatus for stepwise transport of webs of synthetic plastic material or the like

ABSTRACT

Apparatus for stepwise transport of a series of interconnected synthetic thermoplastic containers employs an endless conveyor the upper stretch of which supports and advances the containers past a set of detectors which scan the position of the nearest container during each interval of dwell of the conveyor. The conveyor is driven by a chain which is trained over a gear serving to rotate one sprocket wheel of the conveyor by means of a one-way clutch. The chain is moved lengthwise back and forth by an oscillatory lever and a helical spring. When the spacing between successive containers changes, signals from the detectors cause a deflector to flex the chain with the result that the distance through which the conveyor is advanced is either increased or reduced until the next-following container which moves into the range of the detectors occupies an optimum position. The deflector can be actuated by a fluid-operated motor.

Unite States Patent [191 [111 3,762,617

Maiii'lis 1 1 Oct. 2, 1973 1 1 APPARATUS FOR STEPWISE TRANSPORT PrimaryExaminer-Allen N. Knowles 01F WEBS OF SYNTHETIC PLASTIC MATERIAL OR THELIKE [75] Inventor: Hans Matthis,Kleinheppach,

Germany [73 1 Assign eel Ho fliger 8 z Karg, Waiblingen,

Germany [22] Filed: Mar. 22, 1972 [2]] Appl. No.: 237,130

[30] Foreign Application Priority Data Mar. 24, 1971 Germany P 21 14306.6

[52] 11.5. CI 226/32, 226/34, 226/53, 226/157 51 Int. Cl B65h 23/18 [58]Field of Search 226/32, 34, 157, 226/170, 53; 198/135; 53/51 [56]References Cited UNITED STATES PATENTS 2,821,388 1/1958 Crane et alu226/32 3,635,387 1/1972 Gallistell et a1... 226/157 3,610,499 10/1971Gallistell et a! 226/157 Attorney-Michael S. Striker 57 ABSTRACTApparatus for stepwise transport of a series of interconnected syntheticthermoplastic containers employs an endless conveyor the upper stretchof which supports and advances the containers past a set of detectorswhich scan the position of the nearest container during each interval ofdwell of the conveyor. The conveyor is driven by a chain which istrained over a gear serving to rotate one sprocket wheel of the conveyorby means of a one-way clutch. The chain is moved lengthwise back andforth by an oscillatory lever and a helical spring. When the spacingbetween successive containers changes, signals from the detectors causea deflector to flex the chain with the result that the distance throughwhich the conveyor is advanced is either increased or reduced until thenext-following container which moves into the range of the detectorsoccupies an optimum position. The deflector can be actuated by afluid-operated motor.

10 Claims, 1 Drawing Figure APPARATUS FOR STEIP'WISE TRANSPORT F WEBS01F SYNTHETIC PLASTKC MATERIAL OR THE LIKE BACKGROUND OF THE lNVENTlONThe present invention relates to apparatus for transporting a series ofnormally equidistant commodities in stepwise fashion. More particularly,the invention relates to improvements in apparatus which can be used forstepwise transport of normally (but not necessarily) equidistantportions of strips, webs or the like into register with stationarytreating or processing stations. For example, the apparatus of thepresent invention can be utilized to transport a series of normallyequidistant interconnected plastic receptacles or containers intoregister with one or more stations where the containers can receivecharges of a material which is to be con fined therein, where the filledcontainers can be provided with covers which are sealed thereto toairtightly confine the charges, and where the filled and sealedcontainers can be separated from each other.

In packing apparatus for introduction of foodstuffs or other substancesinto successive containers, particularly into containers which areobtained by deep drawing or analogous deformation of longitudinallyspaced equidistant portions of a web or strip of synthetic thermoplasticmaterial, each of a series of successive containers must be moved intoaccurate register with at least one but normally two, three, four ormore processing stations at which the containers are subjected to one ormore treatments which may involve sterilizing, filling, capping,sealing, providing with indicia, separating from each other and/orothers. A very important prerequisite for proper operation of suchpacking apparatus (particularly as concerns avoiding losses in materialwhich is to be introduced into containers and proper sealing of filledcontainers) is that each container be brought into accurate registerwith the instrumentalities at each treating or processing station. Forexample, it is important to insure that a container which is in theprocess of receiving a charge of liquid and/or solid material bemaintained in accurate alignment with the outlet or outlets of afillingdevice. The same holds true for the sealing station where the freshlyfilled containers must be provided with covers which are thereuponbonded to the web by resorting to one or more welding electrodes or thelike, and also for the cutting or severing station where the'foremostfilled and sealed container or containers are separated from thenext-following containers to be introduced into cartons or the like.

Accurate positioning of such containers with reference to devices atvarious processing stations often presents serious problems, especiallyif the web which is formed with or which carries the containers consistsof synthetic thermoplastic material. In the manufacture of such webs,certain stresses are frozen into their material. During transportthrough the packing apparatus, spaced portions of the web are oftensubjected to more or less pronounced heating action so that such spacedportions undergo more or less pronounced expansion with the result thatthe distance between neighboring containers frequently varies within awide range. This prevents the presently known transporting systems ofsuch apparatus of insuring that each of a series of successivecontainers on or in a web will invariably move into accurate registerwith one two or more successive processing stations.

It was already proposed to compensate for such unpredictable variationsin the spacing between successive containers or analogous commodities bymounting the processing stations on suitable carriages which are movablelengthwise of the path for the web and by providing the apparatus withsuitable detectors which determine the positions of nearest containersand produce signals which are used to adjust the respective stations soas to move their instrumentalities into register with the adjacentcontainers. Such apparatus failed to gain widespread acceptance in the:packing industry because of their complexity as well as high initial andmaintenance cost, especially if an apparatus comprises a large number ofstations.

SUMMARY OF THE INVENTION An object of the invention is to provide asimple, compact, reliable and rugged apparatus which can automaticallycompensate for eventual variations in mutual spacing of a series ofsuccessive commodities, such as a series of deep-drawn receptacles orcontainers which are formed in an elongated web or strip of syntheticplastic material.

Another object of the invention is to provide the apparatus with noveland improved means for automatically adjusting the drive means whichmoves a series of commodities stepwise if the position of a commodityduring an interval of dwell between successive stepwise advancesdeviates from a predetermined optimum position.

A further object of the invention is to provide novel and improvedadjustable drive means for an endless conveyor or analogous carriermeans for a succession of normally equidistant commodities whose mutualspacing is subject to unpredictable variations.

An additional object of the invention is to provide the adjusting meanswith novel and improved means for influencing the operation of the drivemeans.

The invention is embodied in an apparatus for stepwise transport of aseries of normally equidistant commodities whose mutual spacing issubject to variations. The apparatus comprises an endless conveyor oranalogous carrier means for advancing a series of commodities along apredetermined path, adjustable drive means which is operative to movethe carrier means stepwise in a predetermined direction throughdistances of variable length (such distances are normally proportionalto the expected mutual spacing of successive commodities), a pluralityof signal generating detector means adjacent to a portion of the pathfor scanning the positions of successive commodities during theintervals of idleness of the carrier means and for producing signalswhen the position of a commodity occupying the aforementioned portion ofthe path deviates from a predetermined position, and adjusting means foradjusting the drive means in response to signals from the detectormeans.

The drive means preferably comprises an elongated chain or an analogousflexible element which may but need not be finite length, and means formoving the flexible element lengthwise. The adjusting means thenpreferably comprises an idler roller, an idler gear, a sprocket wheel, arunner or an analogous output element which is actuatable in response tosignals from the detector means to thereby deflect the flexible elementwhereby the deflection may result in a shortening of the distancethrough which the carrier means advances a series of commodities or in alengthening of such distance, depending upon whether the signals fromthe detector means indicate that the position of the scanned commoditylags behind or is beyond the predetermined position as considered in thedirection of stepwise movement of the carrier means.

The novel features which are considered as characteristic of theinvention are set forth in particular in the appended claims. Theimproved apparatus itself, however, both as to its construction and itsmode of operation, together with additional features and advantagesthereof, will be best understood upon perusal of the folowing detaileddescription of certain specific embodiments with reference to theaccompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING The single FIGURE is a fragmentarypartly diagrammatic side elevational view of an apparatus which embodiesthe invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The drawing ilustrates aportion of a packing apparatus which is utilized to introduce measuredquantities of a material into successive containers or receptacles 1formed by deep drawing of longitudinally spaced equidistant portions ofa web or strip 2 of synthetic thermoplastic material. The web 2 must betransported stepwise in the direction indicated by arrow A so as toplace successive containers 1 into register with a series of stations ofwhich only one (namely, the station 35) is shown in the drawing. Thestation 35 is assumed to accommodate a suitable filling device (notspecifically shown) which introduces'into containers I measuredquantities of a flowable material, e.g., jam, honey or the like.

The carrier means for directly supporting and advancing the web 2 instepwise fashion comprises an endless conveyor here shown as including achain 3 which is trained over several rotary sprocket wheels 5 (only oneshown) and is provided with a plurality of equidistant outwardlyextending pin-shaped projections 4. The projections 41 may serve tospear one or both marginal portions of the web 2 so that the latter iscompelled to share all lengthwise movements of the upper stretch of thechain 3. The adjustable drive means for intermittently rotating theillustrated sprocket wheel 5 in a counterclockwise direction, as viewedin the drawing, comprises a second rotary sprocket wheel or gear 6 whichis coaxial with the sprocket wheel 5 and is rotatable back and forth bya chain or an analogous flexible element 7 of finite length. The gear 6transmits torque to the sprocket wheel 5 through the intermediary of aone-way clutch 106 which is effective when the gear 6 rotatesanticlockwise but is ineffective when the gear 6 is caused to rotate ina clockwise direction. One end portion of the chain 7 is attached to aresilient element here shown as a helical spring 8 which is anchored ina stationary part 36 of the packing apparatus and which stores energywhen the chain 7 is moved lengthwise to rotate the gear 6 in acounterclockwise direction. The other end portion of the chain 7 isconnected with an adjustable coupling element 9 which is mounted on anoscillatable driving lever 10. The latter is fulcrumed at 10a and has aroller follower 10b which tracks a rotary cam 110. The cam I10cooperates with the spring 8 to pivot the lever 10 back and forth (asindicated by the double-headed arrow B) whereby the chain 7 moveslengthwise back and forth in first and second directions and rotates thesprocket wheel 5 through the intermediary of the gear 6 when the latteris caused to rotate anticlockwise. The coupling element 9 is adjustablelengthwise of the respective arm of the driving lever 10 so as to allowfor rapid and convenient conversion of the packing apparatus forstepwise transport of different types of webs 2, i.e., of webs whereinthe containers l or analogous commodities are nearer to or more distantfrom each other. FOr example, the coupling element 9 may be separablysecured to the driving lever 10 by a screw or the like, and the drivinglever may be provided with a suitably graduated scale to facilitateadjustments of the coupling element 9 for stepwise transport of a giventype of web. The adjusting means for automatically compensating foreventual deviations of the mutual spacing of successive containers 1from a predetermined distance comprises an output element or deflector13 (e.g., a sprocket wheel, a gear, a roller or a runner) which ismovable by the piston rod 11a of a motor here shown as a fluid-operatedcylinder 11. The latter is connected with a source 121 of pressurizedfluid (e.g., compressed air) by means of hoses or conduits 21, 22. Thetwo hoses are connected to each other by a valve 20 (e.g., asolenoid-operated valve) which controls the admission of pressurizedfluid into the lower chamber of the cylinder Ill. When the solenoid ofthe valve 20 is energized in response to a signal which is transmittedby a conductor 19, the conduit 21 can admit pressurized fluid into theconduit 22 so that the piston rod 11a moves upwardly, as viewed in thedrawing, and causes the deflector 13 to engage and flex the chain 7 at apoint between the gear 6 and the coupling element 9.

The deflector 13 is assumed to be a roller or sprocket wheel which isrotatable on a lever 12. One end of the lever 12 is pivotably secured tothe frame of the packing apparatus, as at 38, and its other end isarticulately connected with the piston rod llla.

The apparatus further comprises at least two detectors 14, 15 (e.g.,photoelectric cells) which are adjacent to a portion of the path for web2 and are spaced apart by a distance which is preferably slightly lessthan the normal length of a container 1. The outputs of the detectorsl4, 15 are connected with a suitable evaluating circuit 18 by means ofconductors 16, 17, and the output of the circuit 18 is connected withthe solenoid of the valve 20 (conductor 19).

An idler sprocket wheel 23 is mounted in the frame of the apparatusbetween the coupling element 9 and deflector 13 to insure that theposition of the point where the left-hand portion of the chain 7 movesaway from the gear 6 remains unchanged.

The parts 6, 7, 9, 10, IN) constitute an adjustable drive means for theconveyor or carrier 3-5, and the parts 11, 13, 18, 20 constitute a meansfor adjusting the drive means in response to signals from the detectorsl4, 15.

THE OPERATION The cam 1110 is rotated by the prime mover of the packingapparatus at a selected speed so as to process a desired number ofcontainers 1 or analogous commodities per unit of time. As the cam llltlrotates, it causes the roller follower ltlb to oscillate the drivinglever lltl whereby the lever it) cooperates with the coupling element 9and spring 8 to move the chain 7 lengthwise back and forth as indicatedby the doubleheaded arrow D. When the lever lltl pivots in a clockwisedirection, as viewed in the drawing, the chain 7 causes the gear 6 torotate the sprocket wheel 5 through the intermediary of the clutch we sothat the upper stretch of the chain 3 advances with the web 2 in thedirection indicated by the arrow A. The extent of stepwise movement ofthe chain 3 is determined by the selected distance between the couplingelement 9 and the fulcrum ltla for the driving lever N; such distance isa function of the normal distance between successive containers ll.

The drawing shows the web 2 in a position of rest or dwell between twosuccessive stepwise movements. The system including the detectors M, l5,evaluating circuit 18, valve 20, cylinder ill and deflector llli is idlebecause the container 1f which happens to be adjacent to the detectorsl4, l5 dwells in an optimum or predetermined position, i.e., thecontainer ll" which is located ahead of the scanned container l isassumed to be in accurate register with the filling device at thestation 35. As shown, the lower end portions of the detec' tors 14, 115are inwardly adjacent to the respective transversely extending leadingand trailing marginal or edge portions 24, 25 of the container 1 so thatneither of these detectors furnishes a signal to the evaluating circuit18. The detectors M, 115 are designed, connected in circuit with in andmounted in such a way that they respectively produce signals if theyhappen to register with the edge portions 24, 25 of the nearestcontainer when the chain 3 is at a standstill.

if the chain 3 is arrested while a light beam produced by the lightsource of the detector lid is being reflected on the leading edgeportion 2d of the adjacent container l, the reflected light beamimpinges on the photosensitive element of the detector M and the lattertransmits to the evaluating circuit lid a signal by way of the conductorlb. The circuit W energizes the solenoid of the valve 2% by way of theconductor 19 so that the valve 29 opens and admits a pressurized fluidinto the cylinder l l. The piston rod Illa then pivots the lever 12 in acounterclockwise direction, as viewed in the drawing, so that thedeflector 13 moves to the position 13' and deflects or deforms the chain7 while the driving lever pivots in a first or clockwise direction.Consequently, the extent of lengthwise movement of the chain 7 in afirst direction, namely, against the opposition of the spring 8, exceedsthe normal extent of such movement so that the chain 3 is advancedthrough a slightly greater distance in order to insure that the leadingedge portion 24 of the next-following container or containers i will belocated to the left of the detector 14 when the forward movement of thechain 3 is terminated. The deflecting action of the member i3 ismaintained until the leading edge portion 2d of a container 1 movesbeyond the detector M.

If the chain 3 is arrested at a time when the trailing edge portion 25,of a container 11 is located in the path of the lightbeam issuing fromthe detector 15, the latter transmits a signal by way of the conductor17 so that the evaluating circuit l8 energizes the solenoid of the valve20 in order to move the deflector 13 to the position 13' but at a timewhen the lever it) pivots in a sec- 0nd or counterclockwise direction,i.e., while the gear 6 is rotated clockwise. The deflector i3 isretracted while the driving lever 10 thereupon pivots in a clockwisedirection so that the length of stepwise movement of the chain 3 isreduced with the result that the trailing edge portion 25 of the nextcontainer or containers 1 assumes the position shown in the drawing anddoes not cause the detector 15 to furnish a signal to the evaluatingcircuit 18. Thus, and since the deflector 13 is retracted during forwardtransport of the chain 3, the extent to which the chain 7 is movedagainst the opposition of the spring 8 is less than normally and theextent of forward movement of the chain. 3 is reduced accordingly. Suchoperation is repeated as often as necessary in order to insure that thetrailing edge portion 25 of successive containers 1 do not register withthe detector 15 when the chain 3 is at a standstill.

The detectors l4, l5 and the evaluating circuit 18 can be readilyconstructed and assembled in such a way that the detector 14 producessignals only in response to detection of leading edge portions 24 andthat the detector 15 produces signals only in response to detection oftrailing edge portions 25 on the containers 1. The distance between theillustrated detectors l4, 15 is slightly less than the normal length ofa container, i.e., slightly less than the distance between the leadingand trailing edge portions 24, 25 of a container.

The improved apparatus can be modified in a number of ways withoutdeparting from the spirit of the in vention. For example, the evaluatingcircuit 18 can be operatively connected with the coupling element 9 sothat the latter is automatically adjusted in one direction (e.g., towardthe pivot 10a) in response to a signal from the detector 14 and in theopposite direction in automatic response to a signal from the detector15. Furthermore, the cylinder 11 can be replaced with an electromagnetor other suitable motor means which controls the movements of the outputelement 13 or an analogous deflector. All such modifications will bereadily understood upon perusal of the preceding description.

Without further analysis, the foregoing will so fully reveal the gist ofthe present invention that others can, by applying current knowledge,readily adapt it for various applications without omitting featureswhich fairly constitute essential characteristics of the generic andspecific aspects of my contribution to the art and, therefore, suchadaptations should and are intended to be comprehended within themeaning and range of equivalence of the claims.

What is claimed as new and desired to be protected by Letters Patent isset forth in the appended claims:

ll. In an apparatus for stepwise transport of a series of normallyequidistant receptacles which form part of a web consisting of syntheticthermoplastic material, whose mutual spacing is subject to variationsand which are to be moved seriatim into register with at least onestation, a combination comprising carrier means for advancing saidseries of receptacles along a predetermined path, said carrier meansincluding a conveyor for said web; adjustable drive means operative tomove said conveyor stepwise in predetermined direction through distancesof variable length, comprising an elongated flexible element havingfirst and second ends, a stationary part, resilient means connectingsaid first end to said stationary part and a driving member connectedwith said second end and cooperating with said resilient means to movesaid flexible element in first and second directions through distancescorresponding to the normal spacing between said receptacles wherebysaid web moves insaid predetermined direction in response to eachmovement of said flexible element in said first direction; a pluralityof signal generating detector means adjacent to a portion of said pathfor scanning the positions of successive receptacles during theintervals of idleness of said conveyor and for producing signals whenthe position of a receptacle occupying said portion of said pathdeviates from a predetermined position; and adjusting means foradjusting said drive means in response to said signals, including anoutput element actuatable in response to said signals to deflect saidflexible element not later than or subsequent to a movement of saidflexible element in said first direction.

2. A combination as defined in claim 51, wherein said flexible elementis a chain.

3. A combination as defined in claim 11, wherein said output element isa rotary element.

8. A combination as defined in claim ll, wherein said output element isa runner.

5. A combination as defined in claim 3., wherein said conveyor is idleduring movement of said flexible element in said second direction, saidadjusting means being arranged to move said output element against saidflexible element during movement of said flexible element in said firstdirection when at least one of said detector means generates signalsindicating that the position of the receptacle occupying said portion ofsaid path lags behind said predetermined position.

6. A combination as defined in claim 1, wherein said conveyor is idleduring movement of said flexible element in said second direction, saidadjusting means being arranged to move said output element against saidflexible element during movement of said flexible element in said seconddirection and to disengage said output element from said flexibleelement during the next-following movement of said flexible element insaid first direction when at least one of said detector means generatessignals indicating that the position of the receptacle occupying saidportion of said path is beyond said predetermined position.

7. A combination as defined in claim 1, wherein said adjusting meansfurther comprises fluid-operated motor means for moving said outputelement in response to said signals.

8. A combination as defined in claim 1, wherein the length of eachreceptacle, as considered in said predetermined direction, at leastapproximates a predetermined length and said detector means comprises apair of detectors separated from each other by a distance which is lessthan said predetermined length.

9. A combination as defined in claim 1, wherein said conveyor has anupper stretch arranged to support said series of receptacles and arotary driven member, said drive means further comprising a secondrotary member coaxial with said driven member and one-way clutch meansinterposed between said rotary members, said flexible element beingtrained over said second rotary member and said second rotary memberbeing arranged to rotate said driven member by way of said clutch and tothereby move said upper stretch in said predetermined direction inresponse to movement of said flexible element in said first direction.

10. A combination as defined in claim 1, further comprising means foradjustably coupling said oscillatable driving member with said secondend of said flexible element.

1. In an apparatus for stepwise transport of a series of normallyequidistant receptacles which form part of a web consisting of syntheticthermoplastic material, whose mutual spacing is subject to variationsand which are to be moved seriatim into register with at least onestation, a combination comprising carrier means for advancing saidseries of receptacles along a predetermined path, said carrier meansincluding a conveyor for said web; adjustable drive means operative tomove said conveyor stepwise in predetermined direction through distancesof variable length, comprising an elongated flexible element havingfirst and second ends, a stationary part, resilient means connectingsaid first end to said stationary part and a driving member connectedwith said second end and cooperating with said resilient means to movesaid flexible element in first and second directions through distancescorresponding to the normal spacing between said receptacles wherebysaid web moves in said predetermined direction in response to eachmovement of said flexible element in said first direction; a pluralityof signal generating detector means adjacent to a portion of said pathfor scanning the positions of successive receptacles during theintervals of idleness of said conveyor and for producing signals whenthe position of a receptacle occupying said portion of said pathdeviates from a predetermined position; and adjusting means foradjusting said drive means in response to said signals, including anoutput element actuatable in response to said signals to deflect saidflexible element not later than or subsequent to a movement of saidflexible element in said first direction.
 2. A combination as defined inclaim 1, wherein said flexible element is a chain.
 3. A combination asdefined in claim 1, wherein said output element is a rotary element. 4.A combination as defined in claim 1, wherein said output element is arunner.
 5. A combination as defined in claim 1, wherein said conveyor isidle during movement of said flexible element in said second direction,said adjusting means being arranged to move said output element againstsaid flexible element during movement of said flexible element in saidfirst direction when at least one of said detector means generatessignals indicating that the position of the receptacle occupying saidportion of said path lags behind said predetermined position.
 6. Acombination as defined in claim 1, wherein said conveyor is idle duringmovement of said flexible element in said second direction, saidadjusting means being arranged to move said output element against saidflexible element during movement of said flexible element in said seconddirection and to disengage said output element from said flexibleelement during the nexT-following movement of said flexible element insaid first direction when at least one of said detector means generatessignals indicating that the position of the receptacle occupying saidportion of said path is beyond said predetermined position.
 7. Acombination as defined in claim 1, wherein said adjusting means furthercomprises fluid-operated motor means for moving said output element inresponse to said signals.
 8. A combination as defined in claim 1,wherein the length of each receptacle, as considered in saidpredetermined direction, at least approximates a predetermined lengthand said detector means comprises a pair of detectors separated fromeach other by a distance which is less than said predetermined length.9. A combination as defined in claim 1, wherein said conveyor has anupper stretch arranged to support said series of receptacles and arotary driven member, said drive means further comprising a secondrotary member coaxial with said driven member and one-way clutch meansinterposed between said rotary members, said flexible element beingtrained over said second rotary member and said second rotary memberbeing arranged to rotate said driven member by way of said clutch and tothereby move said upper stretch in said predetermined direction inresponse to movement of said flexible element in said first direction.10. A combination as defined in claim 1, further comprising means foradjustably coupling said oscillatable driving member with said secondend of said flexible element.